Vision information > Human eyesight

Human eyesight is a sense which enables animals to perceive the light, different colors, shapes and it serves to the general perception of the environment. It is oriented mainly towards the perception of contrast and thus even contours and it significantly helps with orientation in space. For a human being the eyesight is the most important sense and that is mainly because almost 80% of information from our surroundings is perceived through it.

The human eye (oculus) is the organ of eyesight and is composed of the eye bulb and additional organs. Photosensitive layer is called the retina and contains photoreceptors, highly specialized photosensitive cells, rods and cones thanks to which the image is created. These cells are embedded in the pigmented epithelium which supplies them with nourishment and light isolation.

Vision itself, individual perception of the light, is based on the sensitivity of the eyesight pigments (e.g. rhodopsin) to the light. Under the influence of light the sight pigments decompose and that triggers the cascade chemical reactions which lead to the change of signal into electric potential, impulse, that carries information to the optical centers of the brain.

For the eyesight perception to be perfect we need also parts of the human eye that form its optical system (cornea, vitreous humor, lens, vitreous body) that collects the rays in the way that their focus is on the retina. A defect of optical system causes inability to create a sharp image on the retina and it leads to refractive errors (short-sightedness, long-sightedness, astigmatism).

Human eye equity is the ability to differentiate between two points in space. It depends on the ability of the optical apparatus to concentrate rays on the retina but also depends on the transparency of the human eye, intensity of light and on density and integration of photoreceptors in the given place on the retina.